pd0 = gro0:

I beleve that the system partition "pd0:" is a gamecart emulator (pd0 is where welcome park app is stored if you dont know) please note that this is all just a theroy and none of this is confirmed but anyway why do i think that? well first let me just say a few facts i know about gamecarts and pd0
1. pd0: Does NOT Change AT ALL when you install a firmware update.
2. pd0: Is different on every console
3. pd0: Has a licence file
4. pd0: has directorys of /app and /licence (it also has /data but thats not important right now)
5. Contents of pd0:app are PFS Encrypted
6. Welcome Park Uses gdb and not what every other system app uses (gda)
now lets look at the contents of a gamecart. (gro0:)
1. gro0: Also doesnt change when you install a system update (Duhh its read only lol)
2. gro0: is different on every gamecart (Even if there the exact same game! with the exact same titleid.)
3. gro0: has a licence file
4. gro0: has directorys /app and /licence (it also has /psp2 but thats just the update file for games that require whatever fw)
5. Contents of gro0:app are PFS encrypted
6. Every single game uses gd however if a gamecart uses category gdb the app installed has no delete button also gda does not work on gamecarts. (Note: gdb can be deleted if installed on ux0 via a .vpk)
so obviously these are pretty damn simular differences right but then why would sony do this and not just put welcome park in vs0:app. - well i think i know why.. and i beleve its for trophys.. you see i think it may just be sony requires anything that can earn trophys to be from PS Store or on a gamecart (or well have the exact same propertys as a gamecart) so yea thats about it for why i think this. also you may be wondering does this mean piracy? well tbh i dont know but im pretty sure thats a no. first off i dont think sony is dumb enough to make it so if we swap all the files in pd0 for one of a gamecarts gro0: that it would just work. and 2. theres simply not enough space on pd0 for this anyway. the pd0 partition is only 300MB. but anyway thats about it for this as i said before this may not be the case its just what i think i have not tested this and cannot test it. (thank sce_pfs)